Disk drives are information storage devices that use magnetic media to store data and a movable read/write transducer positioned over the magnetic media to selectively read data from and write data to the magnetic media.
Consumers are constantly desiring greater storage capacity for such disk drive devices, as well as faster and more accurate reading and writing operations. Thus, disk drive manufacturers have continued to develop higher capacity disk drives by, for example, increasing the recording and reproducing density of the information tracks on the disks by using a narrower track width and/or a narrower track pitch. However, each increase in track density requires that the disk drive device have a corresponding increase in the positional control of the read/write transducer in order to enable quick and accurate reading and writing operations using the higher density disks. As track density increases, it becomes more and more difficult to quickly and accurately position the read/write transducer over the desired information tracks on the disk. Thus, disk drive manufacturers are constantly seeking ways to improve the positional control of the read/write transducer in order to take advantage of the continual increases in track density.
One approach that has been effectively used by disk drive manufacturers to improve the positional control of read/write transducers for higher density disks is to employ a slider and micro-actuator assembly. FIG. 1 provides an illustration of a typical disk drive unit with a slider and micro-actuator assembly. The disk drive device typically has a drive arm 104, a VCM (Voice Coil Motor) 108, a HGA 105 attached to and mounted on the drive arm 104, a stack of magnetic disks 101 suspending the HGA 105, and a spindle motor 102 for spinning the disks 101. The HGA 105 includes the slider and micro-actuator assembly 103 and a suspension 110 (referring to FIG. 2b) to support the slider and micro-actuator assembly 103.
Referring to FIG. 2a, the slider and micro-actuator assembly 103 comprises a substrate 11 having a leading edge and a trailing edge opposite the leading edge, a piezoelectric (PZT) element 15 formed on the trailing edge of the substrate 11, and a read/write transducer 12 formed on the PZT element 15. In the above structure of the slider and micro-actuator assembly 103, the PZT element 15 is sandwiched between the substrate 11 and the read/write transducer 12. Specifically, the PZT element 15 comprises a first electrode layer 15a formed on the trailing edge of the substrate 11, a second electrode layer 15b formed on the read/write transducer 12, and a PZT layer 15c formed between the first electrode layer 15a and the second electrode layer 15b. 
Referring to FIG. 2b, when a voltage is applied to the first electrode layer 15a and the second electrode layer 15b, the PZT element 15 is driven and enables to deform, which accordingly adjusts the position of the read/write transducer 12 relative to the disk 101. However, as the PZT element 15 is located adjacent to the read/write transducer 12, the driving of the PZT element 15 will produce electrical charge and generate a potential voltage, which will make the read/write transducer 12 damaged in case that, for example, ESD (electrical static discharge damage) problem happens.
Hence, it is desired to provide an improved slider and micro-actuator assembly and manufacturing method thereof, a HGA, and a disk drive to solve the above-mentioned problems.